Urinary System Flashcards
(22 cards)
What does the hilus contain in the kidney?
Ureter, nerves, blood, lymphatic vessels
What surrounds the renal sinus? What does it contain and what occupies the renal sinus?
Kidney parenchyma; renal pelvis; loose CT, adipose tissue, blood vessels and nerves;
What does the renal pelvis subdivide into?
Major and minor calyces
What are the two main regions of the kidney? What is a pyramid made up by and where is it found? What makes up a renal lobe? What are medullary rays? What is a renal lobule?
Renal cortex (broad outer zone, renal columns) and renal medulla (has the pyramids with papillae that project into minor calyces with openings of collecting ducts); pyramid with surrounding cortical tissue; medullary tissue projecting into cortex with collecting tubules, prox and distal tubules Medullary ray with surrounding cortical tissue
What is the first part of the nephron? What is the second part?
Forms the urine (Bowman’s capsule to distal tubule); concentration of urinary solutes (collecting system)
What two layers does Bowman’s capsule contain? What makes up the layers? What exists between the two layers?
Parietal and visceral; parietal has simple squamous epi, visceral has podocytes that cover the glomerular capillaries; urinary space
What three things make up the glomerular filtration barrier at the level of the BC? What are the vascular and urinary poles? What is the renal corpuscle made of?
- capillary endothelium (fenestrated, no diaphragms)
- shared basement membrane
- filtration slits between the secondary processes of the podocytes
VP: afferent arteriole enters, efferent arteriole leaves
UP: proximal tubule begins
RC: BC and glomerulus
What portions make up the proximal tubule? What is the epi and cytoplasm? Can you see cell boundaries? What is in the lumen?
Convuluted and a straight portion;
simple cuboidal with brush border; eosinophilic; indistinct; fine precipitated material
What portions does the loop of Henle have? What is the lining of the descending straight portion of prox tubule like? Where is it primarily found? What is the epi of the thin segment?
Descending straight portion of prox tubule, thin segment, ascending straight portion of the distal tubule;
similar to the convoluted portion of the proximal tubule
Medulla; simple squamous
What does the distal tubule consist of? Where is this found mainly? What is the epi? Can you see cell boundaries and precipitate? How are the cell and cytoplasm compared to the proximal tubule?
Ascending straight portion, portion adjacent to renal corpuscle, convoluted part;
Cortex; simple cuboidal epithelium; no, but extensive lateral interdigitations;
cells are smaller and less eosinophilic
Where are collecting tubules found? Ducts? How does epi change in ducts? Can you see cell boundaries? What do the larger ducts do?
Cortex; medulla; cuboidal in tubules to columnar in ducts;
they are visible; comm with minor calyx at area cribrosa
How are nephrons classified? What are the types of nephrons?
Position of renal corpuscles in the cortex;
- superficial (cortical): short loops of Henle; extend a bit into medulla
- juxtamedullary: long loops of Henle penetrating deep into the medulla (hypertonic urine)
- intermediate (midcortical)
What does the juxtaglomerular apparatus make? Where is it located? What are the three main components of the JGA?
Renin; distal tubule returns to renal corpuscle of origin;
macula densa in distal tubule wall, juxtaglomerular cells which are modded SM cells in tunica media of afferent arterioles, extraglomerular mesangial (lacis) cells located at angle between afferent and efferent arterioles
What does renin regulate? What releases them? What system is stimulated and what is ultimately produced? What does this product raise?
fluid and electrolyte balance and BP; juxtaglomerular cells;
Renin-angiotensin system: angiotensinogen (liver) –> angiotensin I –> angiotensin II (via ACE in lung endothelial cells) –> stim zona glomerulosa –> aldosterone –> stim distal tubule to reabsorb sodium and water –> increased intravascular fluid and BP
What does the macula densa do?
Senses changes in NaCl concentration in distal tubule: higher levels inhibit renin secretion, lower vice-versa
Besides dealing with renin-angiotensin system, where does renin also act? What do extraglomerular mesangial cells act?
Afferent arterioles for GFR control;
supportive role, maybe signal integrating system
What is blood circulation in the kidneys?
Renal artery –> A and P division –> interlobar arteries (run in renal columns) –> arcuate arteries (corticomedullary junction) –> interlobular arteries –> afferent arterioles (supply glomerular capillaries and enter RC’s at vascular poles) –> glomerular capillaries –> efferent arterioles –> peritubular capillary network to nourish prox and distal tubules, and vasa recta (countercurrent system)
What does EPO do? What is its synthesis stimulated by? What makes it?
Promote erythrocyte formation in bone marrow (proliferation, differentation, survival of precursor cells);
hypoxia: hemorrhage, erythrocyte destruction, pulmonary function compromised, CHF, altitude;
endothelial cells lining peritubular capillary plexus
What can EPO be used for? What are some of its other uses? What are its downsides?
- anemia of chronic disease 2. postop anemia 3. cancer patients receiving chemo
- neuroprotection 2. treatment of CVD 3. induction of bone remodeling by activating osteoclasts
- Erythrocytosis (increased thrombogenicity) 2. possible tumor growth
Of the minor and major calyces, renal pelvis, ureter, bladder, and urethra, which does not have the same histological structure? What is the mucosa made up of? What is the layer below the mucosa and where is it thickest? What is the adventitia?
Urethra; transitional epi (thickness increases going down, umbrella cells superficially, plasma membrane can stretch and contract, 90% of urinary bladder tumors originate in epi, ATP triggers stretching, apical cyoplasm) and thin lamina propria;
Muscularis in bladder;
CT
How can the male urethra be divided?
Prostatic urethra (transitional epi); membranous urethra (transitional and pseudostratified columnar epi with skeletal muscle surrounding this portion); penile urethra (spong; mostly pseudostratified columnar epi and goes through corpus spongiosum); glands of Littre (mucus-secreting glands)
What is the female urethra lined by? How is it shaped? What muscle is in the wall? What other muscle type is present?
Stratified squamous epi, with some pseudostratified; staghorn-shaped; smooth muscle is thick; skeletal muscle
